1. Field of the Invention
This invention pertains to differential systems for motor vehicles and, more particularly, the invention pertains to end play adjustment systems and methods for axle shafts driven from a differential mechanism.
2. Description of the Prior Art
In conventional drivelines, particularly those for rear wheel drive vehicles, the left-hand and right-hand axle shafts extend laterally from a differential mechanism that includes side bevel gears in continuous meshing engagement with differential pinions supported rotatably on a pinion shaft carried on a differential carrier. The differential carrier is driven rotatably by a set of meshing bevel gears, one of which is driven by a drive shaft disposed substantially perpendicular to the axle shafts. The side bevel gears typically are connected rotatably to the axle shafts by a spline connection formed on a shoulder near the inboard ends of the axle shafts. Each axle shaft carries another shoulder at its axially innermost extremity, the second shoulder located adjacent the differential pinion shaft.
Located between the shoulders on the axle shaft is a recess that is axially aligned with the recess formed on the corresponding side bevel gear. A slotted washer, fitted within the recesses of the axle shaft and side bevel gear, limits outward axial movement of the axle shaft relative to the side bevel gear. However, because the recess formed on each bevel gear that receives the slotted washer is open at its axially inner surface, each axle shaft is free to move along the spline connection axially inward toward the differential pinion shaft.
Thus, there is a tendency for wear in the differential assemblies to cause play allowing the side yokes to shift axially inwardly relative to the differential case and jar or knock against the pinion shaft. It is possible that the axle shaft button of the conventional C-ring design can break off due to stress riser in which case the axle will exit the differential assembly. Moreover, the conventional assembly can lead to grinding away of the end of the side yoke causing excessive negative camber, which in turn can lead to uneven tire wear and poor driving stability. It can also cause particles of the side yokes to embed themselves in the differential clutch plates causing slippage of the differential unit resulting in a clunking or thumping noise. If the wear is left unchecked, it may increase to a point where the flange will shear or cut into the differential case causing a leakage of fluid and ultimately leading to complete destruction of the differential assembly.
The need exists for a solution to the problem of stress risers and side yoke wear caused by grinding of the yoke end against the differential pinion shaft which does not involve having to replace an entire side yoke.
It is an object of the present invention to provide means for limiting displacement of an axle shaft in both axial directions.
A device, according to the present invention, for limiting axial displacement of an axle shaft in a differential mechanism includes a shaft supported for rotation about a longitudinal axis having a threaded portion located near an axial end of the shaft to support a washer and a threaded adjustment member threadingly engaging the end of the axle shaft adjacent the differential pinion shaft.
The preferred embodiments of the present invention include adjustment members threaded onto the interior axial end of the axle shaft and, alternatively, an adjustment member that respectively engage the associated side gear through a splined interface. With these embodiments, the method of assembly is preformed in the following manner: the cross pin is pulled out of the case, and the shafts one at a time are inserted through the side gears where the adjustment member (collar) is fully threaded onto the shaft. The shaft is then pulled outboard until the spline on the adjustment member makes contact with the side gear spline. The adjustment member is then turned counterclockwise just enough to engage the splines. The shaft is then pulled outboard until the adjustment member flange abuts the side gear. The same procedure is then repeated for the other axle. Then the cross pin is assembled and locked in place.
With this arrangement, inboard movement of the shaft is confined to allow the splined feature of the adjustment member to keep the adjustment member from unthreading.
These and other structural and functional benefits of the present invention will become apparent from the following description and associated drawings.